Crane fly larvae, known as leatherjackets, are one of the most destructive underground pests a lawn can face, chewing through grass roots in fall and spring before emerging as harmless but annoying adults. The frustration of watching healthy turf turn brown and patchy despite watering and feeding points directly to a failed control strategy — the wrong insecticide applied too late in the season.
I’m Mohammad Maruf — the founder and writer behind Gardening Beyond. I spend my time digging through product registrations, EPA labels, active ingredient concentrations, and real-world user reports across thousands of garden pest scenarios so you don’t have to guess which chemistry actually stops leatherjackets at the soil level.
This guide breaks down the five most effective formulations for killing crane fly larvae in lawns and ornamentals, comparing residual duration, application method, and coverage area to help you choose the right insecticide for crane flies this season.
How To Choose The Best Insecticide For Crane Flies
Leatherjackets live in the top inch of soil, so surface sprays and short-residual products often miss them entirely. You need a product that either infiltrates the thatch layer (liquid concentrate) or releases active ingredient as granules dissolve into the soil. Timing, persistence, and chemistry define success.
Active Ingredient: Which Chemistry Stops Larvae?
Bifenthrin, permethrin, and acephate are the three most common active ingredients in this category. Bifenthrin offers the longest residual — up to three months in soil — making it ideal for early-fall preventive applications. Permethrin works well for spot treatments with a shorter residual of roughly four weeks. Acephate is systemic, meaning it moves through the plant, but its odor and potential leaf burn require careful application timing (dusk or shaded areas).
Application Method: Granules vs Concentrate
Granules, spread with a walk-behind or handheld spreader, release insecticide slowly as they dissolve, providing uniform coverage on large lawns (5,000 to 10,000 sq ft). Liquid concentrates, mixed with water and applied via sprayer, penetrate thatch faster and work well on flower beds, perimeter strips, and smaller turf areas where granular spread patterns may be uneven.
Residual Duration and Reapplication Schedule
Crane fly larvae feed from late summer through early spring. A product with three-month residual (like Ortho Lawn Insect Killer Granules) lets you apply once in early fall and skip winter reapplication. Shorter-residual products (4 to 6 weeks) require bi-monthly follow-up. Check the label for “days to control” or “weeks of residual” — generic claims like “long lasting” mean nothing without a number.
Quick Comparison
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| Model | Category | Best For | Key Spec | Amazon |
|---|---|---|---|---|
| Ortho Bug B Gon Max Insect Killer for Lawns | Granular | Large lawns up to 10,000 sq ft | 3-month residual, kills 100+ insects | Amazon |
| Bonide Systemic Insect Control Concentrate | Liquid Concentrate | Ornamentals and flower beds | 16 oz makes 16 gallons; acephate systemic | Amazon |
| Ortho Lawn Insect Killer Granules | Granular | General lawn protection | 10 lbs covers 10,000 sq ft; 3-month control | Amazon |
| Compare-N-Save Concentrate | Liquid Concentrate | Large-area liquid coverage | 32 oz makes 176 gallons; covers 176,000 sq ft | Amazon |
| Martin’s Permethrin 13.3% Concentrate | Liquid Concentrate | Controlling larvae near gardens | 32 oz; 4-week residual; lower toxicity to animals | Amazon |
In‑Depth Reviews
1. Ortho Bug B Gon Max Insect Killer for Lawns
The Ortho Bug B Gon Max delivers a bifenthrin-based granular formulation that kills leatherjackets both above and below the soil line for up to three months — the longest residual in this comparison. A single 10 lb bag treats the full 10,000 sq ft, making it the ideal choice for one-application-per-season protection against crane fly larvae.
Users consistently report seeing reduced pest pressure within days of watering in the granules, with effects holding through the critical fall feeding window. The product is labeled for use on lawns, ornamentals, flower beds, and vegetable garden perimeters, so you can cover the entire property without switching products.
Owners note that ants may require a second application if they return after the initial treatment, but the overall suppression of ticks, fleas, and flying beetles has been excellent for years. A few long-term users mention that pricing varies by retailer, so compare before buying.
What works
- Three-month residual covers fall and spring feeding
- Treats 10,000 sq ft per bag
- Safe for lawns, ornamentals, and vegetable gardens after drying
What doesn’t
- Ants may return and require reapplication
- Requires thorough watering after spreading
2. Bonide Systemic Insect Control Concentrate
The Bonide systemic concentrate uses acephate, which the plant absorbs and moves through its tissues, making it effective against larvae feeding on roots and stems of ornamentals. Each 16 oz bottle mixes to produce 16 gallons of spray, and it carries an EPA registration that covers thrips, mealybugs, scale, and two-spotted spider mites alongside general caterpillar-type larvae.
Users rave about how quickly it stops fungus gnats and leaf-rolling worms on canna lilies, though several warn that the smell is extreme — described as like a hot dumpster or dog accident — so plan to apply in the evening and avoid areas where you’ll sit or entertain for a few hours. The product is not intended for vegetable or fruit plants, stick to flower beds, roses, shrubs, and other ornamentals.
One practical tip from experienced users: spray when the sun is low or the area is shaded to prevent leaf burn from the acephate reacting with direct UV. Weekly reapplication is recommended while the infestation persists.
What works
- Systemic action targets hidden larvae inside plant tissue
- Fast knockdown of caterpillars and worms
- Small bottle makes a useful amount of spray
What doesn’t
- Strong, unpleasant odor
- Not for use on vegetables or fruits
- Can burn leaves if applied in direct sun
3. Compare-N-Save Concentrate Indoor & Outdoor Insect Control
The Compare-N-Save concentrate delivers bifenthrin in a 32 oz bottle that mixes to produce an enormous 176 gallons of ready-to-use spray — enough to cover 176,000 sq ft. That’s the highest volume-to-coverage ratio in this lineup, making it the economical choice for large properties where crane fly larvae have a wide territory to destroy.
Users report immediate knockdown of mosquitoes and fleas, with a visible difference within hours of application. The product can be mixed with insect growth regulators for even longer suppression. Many owners use it in a backpack sprayer for perimeter treatments around the house, lawn, and garden beds, noting that reapplication every 7–10 days is necessary for sustained control because the residual is shorter than granular options.
A few buyers mention that they wish the residual lasted longer than a week for mosquitoes, but for crane fly larvae specifically, the bifenthrin chemistry still kills on contact and provides good suppression during the treatment window. The versatility for both indoor and outdoor use adds convenience if you manage multiple pest types.
What works
- Massive coverage — 176 gallons from one bottle
- Kills on contact; good for large turf areas
- Can be tank-mixed with growth regulators
What doesn’t
- Requires weekly reapplications for full control
- Strong chemical odor during mixing
4. Ortho Lawn Insect Killer Granules
The Ortho Lawn Insect Killer Granules are a bifenthrin-based granular product that kills by contact and works both above and below ground. It provides three months of residual control for listed ants, spiders, ticks, pillbugs, and scorpions — and the same barrier chemistry stops leatherjackets from feeding on grass roots during their larval stage.
Users highlight how easy it is to apply with a standard Scotts spreader; a single 10 lb bag covers the full 10,000 sq ft of lawn. One reviewer with a small dog mentioned that their yard had zero ticks for several months after a single application, and the fleas that were biting the dog disappeared entirely.
A small number of buyers noted that ants and some tougher species may require a follow-up treatment, but for general lawn protection against crane fly larvae and other turf pests, the granular application is simple, quick, and long-lasting. The main caution is to water the granules in immediately and keep people and pets off until the area dries completely.
What works
- Three-month residual with one application
- Easy to spread with a standard spreader
- Controls a broad spectrum of lawn insects
What doesn’t
- Heavy rain before watering-in reduces effectiveness
- Some insects may need a second treatment
5. Martin’s Permethrin 13.3% Concentrate
Martin’s Permethrin 13.3% Concentrate offers a synthetic pyrethroid that mimics natural chrysanthemum compounds, giving it a lower toxicity profile for mammals while still killing crane fly larvae effectively. The three active-ounce bottle mixes into a 32 oz container that controls pests for up to 4 weeks per application — shorter than bifenthrin but gentler around pets and chickens.
Owners who use this product in a chemical mister for yard perimeter, chicken run, and dog areas report fantastic tick control for 4 to 6 weeks per application. The label advises mixing 1.5 oz per gallon of water and spraying at dusk or dawn to protect beneficial bees. It works well for spot-treating the lawn edges where leatherjackets often concentrate.
Some users note the strong paint-thinner smell, which seems more intense than earlier batches, so outdoor application and a breathing mask are recommended. It is ineffective against ants, crickets, roaches, and spiders, so keep that in mind if you’re trying to cover multiple pest types with one product.
What works
- Low toxicity to mammals, suits pet owners
- Effective tick and mosquito control for weeks
- Can be applied with backpack or hand sprayer
What doesn’t
- Short 4-week residual needs reapplication
- Strong chemical odor
- Not effective on ants or spiders
Hardware & Specs Guide
Granular vs Liquid Concentrate
Granules (such as Ortho Bug B Gon Max and Ortho Lawn Insect Killer) release active ingredient slowly as they dissolve in water, giving you 3-month residual. Liquid concentrates (Bonide Systemic, Compare-N-Save, Martin’s Permethrin) provide faster thatch penetration but require more frequent reapplication. For most homeowners managing crane fly larvae, one spring/fall granular application is simpler and more effective than monthly liquid spraying.
Active Ingredient Chemistry
Bifenthrin (used in Ortho products and Compare-N-Save) offers the longest soil residual at 3 months. Acephate (Bonide) is systemic and moves through the plant but has a strong odor and can burn leaves in direct sun. Permethrin (Martin’s) breaks down faster in sunlight and soil, lasting about 4 weeks, but has a better safety profile for mammals. Match the chemistry to your reapplication willingness and the sensitivity of nearby plants.
FAQ
When is the best time to apply insecticide for crane flies?
Can I use a general lawn insecticide for crane fly larvae?
How long does it take for granules to kill crane fly larvae?
Is permethrin safe to use around pets and vegetable gardens?
Final Thoughts: The Verdict
For most gardeners, the insecticide for crane flies winner is the Ortho Bug B Gon Max Insect Killer for Lawns because it provides three-month residual control in an easy granular application that covers the full 10,000 sq ft lawn in one treatment. If you want systemic action inside ornamentals, grab the Bonide Systemic Insect Control Concentrate. And for property-wide coverage at the lowest cost per gallon, nothing beats the Compare-N-Save Concentrate.